Paraffinic jet fuel by hydrocracking wax



Aug. 23, 1966 w. F. AREY. JR.. ET AL 3,263,436

PARAFFINI C JET FUEL BY HYDROCRACKING WAX Filed Feb. 25. 1964 2 Sheets-Sheet 1 [I E r: g E 3 a CD a E m In In 3 T N In In N N J *l N M N N k N a 2 :2 F5 LL O q N 2 S g E 1 11 g 3 WILLIAM FLOYD AREY, JR. [NVENTQRS GLEN PORTER AMNER 666 M PATENT ATTOR N EY 3, 1966 w. F. AREY. JR, ET AL 3,268,436

PARAFFINIC JET FUEL BY HYDROCRACKING WAX Filed Feb. 25. 1964 2 Sheets-Sheet 2 [I [U P. 5 d 5 3 D LL 0 9 CU of J a $6 N D 8 a (.0 I!) u: (D

\ Q (.0 5 3 h 0 GD 0 N: (D 33 R V cm r: L 2 2 5 u 0 O 0: N D In K s x g z T 5 ga Q Q 2 2 WILLIAM FLOYD AREY, JR. |NVENTQRS g :3 GLEN PO TER HAMNER g: Q (5% O I PATENT ATTORNEY United States Patent 3,268,436 PARAFFINIC JET FUEL BY HYDROCRACKING WAX William Floyd Arey, In, and Glen Porter Hamner, Baton Rouge, La., assiguors to Esso Research and Engineering Company, a corporation of Delaware Filed Feb. 25, 1964, Ser. No. 347,194 9 Claims. (Cl. 208-59) This invention is directed to fuels utilizable in jet combustion devices. It is more particularly concerned with an improved process whereby there are produced jet fuels from parafiin waxes found in petroleum.

Paraflin wax is a normally solid wax-like substance composed of high molecular weight hydrocarbons. It is called parafiin wax to distinguish it from the vegetable and animal waxes which are composed largely of oxygenated compounds. It is usually obtained from the heavier fractions of petroleum such as are used for the production of lubricating oils as well as certain burning oils. In nearly every case, it is an undesired constituent in such oils and is removed by known so-called dewaxing methods during refining. While paraffin wax is useful for many purposes such as sealing containers, production of waxed paper, production of water-proofed cartons and the like, and finds a large and wide use, there is still a considerable amount of paraffin wax from which there is no ready market.

Various processes have been proposed for the treatment of conversion of parafiin wax. Those processes resulting in a hydrocarbon product generally involve a refining operation which produces a normally solid Wax of improved characteristics, or a more drastic conversion treatment which results in the production of a liquid product. The former usually comprises such steps as solvent extraction, fractional crystallization, clay treatment and the like, in which the structure of the hydrocarbons is unaltered. The latter involves a step in which the hydrocarbons are decomposed or split to give a wide range of products comprising normally gaseous and normally liquid products, most of which are of relatively low value. It would be most advantageous to have a practical process whereby parafiin wax could be converted into more valuable hydrocarbon products. One possibility lies in its conversion to -fuels utilizable in jet combustion devices.

As is well known in the art, the term jet combustion, refers to a method of combustion wherein fuel is con tinuously introduced into and continuously burned in a confined space, for the purpose of deriving power directly from the hot products of combustion. The most complicated forms of jet engines presently proposed consist of a propulsion or jet tube, closed at one end, plus a gas turbine which extracts sufiicient energy from the departing gases to drive the compressor. In present commercial forms, the compressor and turbine are assembled axially upon a common shaft, spaced far enough apart to permit a number of combustion chambers to be arranged about the shaft between the compressor and turbine, with an exhaust tube extending rearwardly from the turbine. The principal application of such engines is in powering aircraft, particularly for high-altitude operations. Therefore, the desiderata of fuels utilizable in jet combustion devices are many and varied.

One of the problems encountered in the employment "ice of fuels in jet combustion devices is their tendency to form carbon upon combustion. The carbon thus formed creates noxious exhaust smoke which is highly undesirable. The combustionaformed carbon is also deposited inside the combustion zone Where it interferes with the operation of the device and may also contribute to the warping of parts in the zone by causing uneven heating.

A standard indication of the carbon-forming tendency of a fuel is its luminosity number. As this standard is directly related to the burning qualities desired in a jet fuel, it is apparent why such standard is an important factor in jet fuel specifications. The normal commercial kerosene fraction has a luminosity number that is relatively low and, therefore, requires extensive improvement prior to use as a jet fuel. It is highly desirable, therefore, to produce a jet fuel having a high luminosity number, and especially desirable to produce such a jet fuel from the paraflin wax mentioned above.

It is an object of this invention, therefore, to provide an improved jet combustion cfuel. Another object is to provide a simple process for producing an improved lower boiling range jet fuel from paraflin wax stocks. Another object is to provide a jet fuel of improved properties, that is, obtained by hydrocracking paraffin wax in the presence of hydrogen and of a suitable hydrocracking catalyst. Still another object is to provide a process for producing improved jet combustion fuels having high luminosity numbers from undesirable paraflin Wax stocks that involves cracking such paraffin wax stocks in the presence of hydrogen and a hydrocracking catalyst. Another object is to provide jet combustion fuels having high luminosity numbers which are produced by such process.

Other objects and advantages of the present invention will become apparent to those skilled in the art from the ttollowing detailed description considered in conjunction with the drawings which shows schematic arrangements of typical embodiments for carrying out the process of this invention.

It has now been found that jet fuels can be produced by hydrocracking a parafiin wax charge stock in the presence of a cracking catalyst, preferably a nickel or palladium series metal catalyst, which method is simple and economical and which simultaneously provides for the utilization of heretofore undesirable paraffin wax.

In general, the present invention provides a method for producing a jet combustion fuel which comprises contacting a parafiin wax charge stock with a hydrocracking catalyst in the presence of hydrogen in amounts of from about 2000 to 20,000 s.c. f. of hydrogen per barrel of wax charge stock to convert at least a portion of the hydrocarbon charge into a jet fuel boiling within the range varying between about F. and about 550 F. Broadly, the operating conditions utilized in said contacting are temperatures of from about 300 to 900 F., pressures of from about 500 to 3000 p.s.i.g. and flow rates within the range of about 0.1 to 10 v./v./hr. Suitable catalysts include supported platinum metal series, e.g., platinum, palladium or nickel catalysts as well as other sulfur insensitive hydrocracking catalyst of the copper, cobalt and iron salts of the oxy and thio acids of chromium, molybdenum, and/or tungsten. The sulfided forms of the foregoing are found to be effective. Generally any one or a combination of the above active components may be used either alone, i.e. unsupported, or

together with supports such as alumina, alumino-silicate zeolites, diatornaceous earth, treated clay, activated carbon or the like. In addition, the use of the zinc, magnesi-um, calcium, strontium, or hydrogen form of synthetic faujasite as a catalyst support may be desirable.

Within the narrower limits of the broad range of conditions listed above, the conditions are not independently variable. It is, therefore, necessary to select conditions from within the ranges specified to accomplish the desired hydrooraoking of the Wax stock as evidenced by the formation of the high quality paraflinic jet fuel and produce but small amounts of aromatics. The interdependence of these variables will be more clearly understood by reference to the discussion following and to the accompanying illustrative examples.

The process of this invention is applicable for the hydrocracking of any normally solid hydrocarbon wax, that is, any hydrocarbon wax having a boiling point of 650 F. or over. The wax will usually be derived from natural mineral sources such as petroleum, oil shale, oil from tar sands, gilsonite, ozokerite, or the like, but synthetic wax produced by the Fischer-Tropsch synthesis or as a by-product of other processes may also be utilized. The process may be applied for the hydrocracking of crude so-called slack wax, or to refined waxes of various melting points or to so-called residue wax. While the various waxes differ somewhat in properties, i.e., melting point and hardness, they are all composed of hydrocarbons containing long parafiin chains. In some parafiin waxes the chains may be slightly branched and in some the chains may :be attached to naphthenic or aromatic groups. Olefinic groups are rarely present; when present they do not affect the operation of the process.

The process is particularly applicable to high molecular weight wax, recover from residual crude oil fractions, boiling above about 650 F., preferably above about 1000 F., and up to about 1300 F., which are known as microcrystalline wax or as soft microwax petrolatum. This feed is a black to brown colored, gelatinous, oily, translucent, semi-solid, amorphous mass whose consistency varies with the temperature. It is obtained by dewaxing a residual crude oil fraction boiling above about 1000 F. In simplest terms, it is a microwax obtained from a dewaxing operation which has not been deoiled and therefore contains from about to 50 Wt. percent oil, preferably about 20 percent oil.

In accordance with the present invention there is employed as an outstanding hydrocracking catalyst a composition comprising a metal or compound of the platinum group deposited on, composited with, or incorporated Within, a crystalline silica-alumina anionic network which has uniform size pore openings between about 6 and Angstrom units. The crystalline nature of the catalyst is important, as the particular crystalline structure will then control the uniformity of the pore openings, and so distinguish it from other crystalline and non-crystalline zeolitic materials and from amorphous silicaalumina gel catalysts and aluminas. In this regard, then, the actual chemical composition of the support becomes of secondary value compared to the size of the pore openings. By this is meant that the relative amounts of silica and alumina are not of primary importance though these do play a role in both catalyst stability and activity.

In a crystalline alumino-silicate zeolite the actual structure comprises an anionic network with cations interspersed to allow electrical neutrality. Normally, as prepared, these cations are sodium. In the structure, the amount of sodium present has the same atom content as the aluminum because the aluminum atom being trivalent needs an additional charge to be present to compensate for its deficiency in relation to the quadrivalent silicon atoms. Thus, for the purposes of the present invention the catalyst support is derived from a crystalline zeolite having a nominal anhydrous composition of where the relative silica content may vary at will, providing the port size opening of the crystalline material remains in the 6 to 15 Angstrom unit region. Nominally, for a good hydrocracking process catalyst support, the soda content is too high, but it can be reduced to an acceptable level by base exchanging with a more acceptable cation, such as ammonium or hydrogen ions. This does not preclude the use of other metal cations in this base exchange operation which could serve as catalytic agents in their own right as well as improving the properties of the alumino-silicate crystals as a support. Examples of methods of preparing the catalysts utilizable in the present invention are set forth in U.S. Serial No. 122,089, filed in the U.S. on July 6, 1961, by E. M. Gladrow and P. T. Parker.

As heretofore mentioned, the catalyst of the present invention may be subject to many variations Without departing from its spirit. Though it finds its highest utility when a hydrogen ion replaces the bulk of the sodium ions in the original sodium alumino-silicate, under certain circumstances it may be desirable to replace the sodium by other elements such as cobalt, nickel, zinc, magnesium, calcium, cadmium, copper, and barium, as well as the oxides and sulfides thereof and employ the resulting crystalline compositions as a support for the platinum group metals. Such materials serve not only as the support for the platinum group metal catalyst, but also possess catalytic activity in their own right. Thus, such catalysts may serve a dual role for specific hydrocarbon conversion reactions. The other metal modifications of the adsorbent may impart greater thermal stability to the noble metal catalyst composite.

In addition to the alumino-silicate Zeolite supports disclosed above, other supports advantageous for use in this invention include a number of conventional carrier materials heretofore employed. The carrier may be selected from activated alumina, activated bauxite, silica gel, diatomaceous earth, treated clay, hydrogen fluoride promoted alumina, activated carbon, and the like. Of the foregoing, alumina is the carrier material particularly preferred as a support.

Also suitable for use as catalysts in the instant invention are the unsupported catalyst. Thus, unsupported metals of the platinum group of oxides and sulfides or mixtures thereof may be empolyed for the process of this invention. In this regard, it is found that molybdenum sulfide, nickel sulfide, or mixtures thereof are preferred for use as a catalyst.

Having generally described the nature of the invention as well as the parafiinic wax charge stock and catalyst employed therein, attention is now directed toward a detailed discussion of the invention. In order to aid in this discussion, reference is made to the attached FIGURES l and 2 which illustrate diagrammatically a process flow plan of the manner in which the present hydrocracking reaction is preferably employed to produce highly desirable jet fuels.

Referring to FIGURE 1, a suitable paratfinic wax charge is introduced through a pipe 10 and pumped by means of a suitable pumping device 11 through a pipe 12 into a heater 13. In the heater 13 the charge is heated to reactor temperature of from 350 to 900 F. preferably 500 to 750 F. The thus heated charge is then passed through pipes 14 and 15 into a reactor 16. Simultaneously, hydrogen gas or a gas rich in hydrogen is introduced into pipe 17 and pumped and compressed by means of a compressor 18. The compressed hydrogen passes through a pipe 19 into a heat exchanger or heating device 20, wherein it is heated to the above reaction temperature. The thus heated hydrogen is then comingled with the wax charge in pipe 15 and the mixture then passes into the reactor 16.

The reactor 16 can be a single reactor or comprise a plurality of reaction beds. In the reactor 16 there is contained a bed or plurality of beds of a suitable hydroa cracking catalyst, such as palladium on hydrogen form faujasite support or nickel sulfide on silica/ alumina support as hereinbefore described. The mixture of hydrogen and paraffin wax charge is contacted with the catalyst in the reactor 16 under suitable conditions to effect at least partial conversion of the parafiin wax charge into a lower boiling range jet fuel. Suitable operating conditions include:

Temperatures of from 300 to 900 F., preferably 500 to Pressures of from 500 to 3000 p.s.i.g., preferably 1000 to 2000 p.s.i.g.

Flow rates of from 0.1 to v./v./hr., preferably 0.5 to

2 v./v./hr.

Hydrogen feed rates of from 2000 to 20,000 s.c.f. H /bbl.,

preferably 3000 to 10,000 s.c.f. H /bbl.

According to the present invention, hydrocracking of paraflinic wax charge stock with consequent improvement in burning qualities, i.e., higher luminosity number, can be accomplished by contacting such charge stock with the catalysts and at the operating conditions as hereinbefore set forth. Generally speaking, improvement in burning qualities, i.e., higher luminosity number, can be obtained by operating at relatively higher hydrogen feed rates, higher pressures and relatively milder temperatures to give a luminosity number of at least 65. Accordingly, the degree of conversion used will depend upon the amount of jet fuel desired in a specific operation.

The total effluent from the reactor 16 is removed through a pipe 21 and passed into a heat exchanger or suitable cooling device 22. In the heat exchanger 22, the effiuent is cooled to temperatures at which gaseous hydrogen can be separated from liquid phase, i.e., temperatures below about 150 F. The thus cooled efiluent is passed through a pipe 23 into a high pressure separator 24. In the high pressure separator 24, there are a liquid phase and a gaseous phase. The gaseous phase cont-aining substantial amounts of hydrogen is removed through a pipe 25 and can be recycled to the process through pipe 19. The liquid product from the high pressure separator 24 is removed through pipe 26, passed through a depressuring zone 27, and then through pipe 28 into a suitable fractionating device 29.

In the fractionator 29, the liquid products are separated into suitable fractions. C and lighter fractions, i.e., for example, butanes and dry gas are removed through pipe 30 and can be sent to the gas processing plant. In accordance with the invention, a high quality jet fuel boiling in a range between about 50 to 480 F., is removed through pipe 31. The material boiling at temperatures higher than about 480 F. is removed through pipes 32 and 33. If desired, this material can be recycled through the process via pipes 34 and 10.

FIGURE 2 illustrates an alternate method of producing jet fuels in accordance with this invention, but which involves the use of two reactors. According to this embodiment, a suitable parafiinic Wax charge is introduced through a pipe and pumped by means of a suitable pumping device 41 through a pipe 42 into a heater 43. In the heater 43 the charge is heated to reactor temperature of from 400 to 900 F. preferably 500 to 750 F. The thus heated charge is then passed through pipes 44 and 45 into a first reactor 46. Simultaneously, hydrogen gas, or a gas rich in hydrogen, is introduced into pipe 47 and pumped and compressed by means of a compressor 48. The compressed hydrogen passes through a pipe 49 into a heat exchanger or heating device 50 wherein it is heated to the above reactor temperature. The heated hydrogen is then co-mingled with the wax charge in pipe 45 and the mixture then passes into the first reactor 46.

In the reactor 46 there is contained a bed or plurality of beds of a suitable hydrocracking catalyst and in this embodiment palladium on hydrogen form of faujasite support as hereinbefore described the mixture of hydrogen and parafin Wax charge is' contacted with the catalyst in the reactor 46 under suitable conditions to effect at least partial conversion of the paraffin wax charge into a lower boiling range jet fuel. Suitable operating conditions in this embodiment include:

Temperatures of from 400 to 800 F., preferably 550 to 750 F.

Pressures of from 500 to 5000 p.s.i.g., preferably 1000 to 3000 p.s.i.g.

Flow rates of from 0.2 to 20 v./v./hr., preferably 0.5 to

2 v./v./hr.

Hydrogen feed rates of from 2000 to 20,000 s.c.f. H /bbl.,

preferably 3000 to 10,000 s.c.f. H /bbl.

The total effluent from the reactor 46 is removed through a pipe 51 and passed into a heat exchanger or suitable cooling device 52. In the heat exchanger 52, the effluent is cooled to temperatures at which gaseous hydrogen can be separated from liquid phase, i.e., temperatures below 150 F. The thus cooled efiluent is passed through a pipe 53 into a high pressure separator 54. In the high pressure separator 54, there are a liquid phase and a gaseous phase. The gaseous phase containing substantial amounts of hydrogen is removed through a pipe 55 and can be recycled to the process through pipe 49. A liquid product from the high pressure separator 54 is removed through a pipe 56, passed through a depressurim zone 57, and then through a pipe 58 into a suitable fractionating device 59.

In the fractionator 59, the liquid products are separated into suitable fractions. C and lighter fractions are removed through pipe 60; the high quality jet fuel boiling in a range between about 50 to 480 F. is removed via pipe 61; and a portion of the material boiling at temperatures higher than about 480 F. is removed via pipes62 and 63.

In accordance with this embodiment, at least a portion of material boiling at temperatures higher than about 480 F. is pumped by means of pumping device 64 through pipe 65 to heater 66. In the heater this charge is heated to a temperature of from about 450 to 800 F., preferably 550 to 750 F. The heated stock is then passed via pipes 67 and 68 into a second reactor 69. At the same time, hydrogen is introduced into pipe 70 and is pumped and compressed by means of compressor 71. The compressed hydrogen is passed via line 72 into heating device 73 where it is heated to reactor temperature. The thus heated hydrogen is co-mingled with the high boiling material in pipe 67 and the mixture passes into the second reactor via line 68.

In the second reactor 69, there is contained a bed or beds of suitable hydrocracking catalyst, preferably one different from that utilized in the first reactor 46. Thus in this embodiment reactor 69 contains a catalyst-comprising nickel sulfide on silica/alumina support. The mixture of hydrogen and lower boiling materials is contacted with said catalyst in the second reactor 69 under operating conditions not unlike those employed in first reactor 46. The total efifluent from reactor 69 is removed through line 74 and any gaseous hydrogen contained therein is removed in the manner hereinbefore described. The remaining liquid product is passed via line 74 from where it is introduced into line 51 for further processing.

The following examples are presented to better illus trate the effects of the several process variables upon the quality of the jet fuel product produced. These examples will further serve as a demonstration of the unexpected results, e.g., luminosity number, obtained when'hydrocracking the parafiin Wax feed under the operating conditions of this invention.

EXAMPLE I This example serves as a comparison of operating conditions and their effect on the quality of jet fuel produced by hydrocracking. In the example, a micro wax feed having the following inspections was employed.

Micro wax feed inspections Gravity, API 32.8 SSU 210 F. 104 Melt point, F. 177 Oil content, Wt. percent 2 Initial boiling point, F. 950

This Wex feed was hydrocracked (run No. 1)'in accordance with the process conditions of this invention. A similar feed was also hydrocracked, but instead employing lower pressures, higher temperatures, lower flow rate, etc. (run No. 2). The process conditions utilized the product distribution and resulting inspections are set forth below in tabular form.

TABLE I Feed Micro Wax Catalyst Pd on Hydrogen-Form Faujasite Run No. 1 Run No. 2

Operating Conditions:

Temperature F 600 675 V./v./hr 1 0. 5 Pressure, 1, 000 100 By, s.c.f./bb 6, 000 400 Product Distribu percent:

Ca and Lighter 13. 7. 2 C4 15. 5 10. 2 0 470... 38. 6 17. 6 47 F. 32. 9 65.0 Jet Fuel Inspections Gravity. 68-69 69.5 Freezing Point, 88 8S Lumiuometer N o 95 70-75 Composition, vol. percent:

Aromatics 2 10-12 Naphthene 16-18 Paraflfins 78 65-70 It is readily apparent from the above data that when operating at low pressure, high temperature, etc. with palladium on hydrogen form faujasite as a catalyst, a lower conversion to poorer quality jet fuel is realized. This is surprising since much of the art on wax conversion using other catalyst preferred low pressure and higher temperatures for operating conditions. The purpose of the art, however, was to convert wax to low boiling lube oil through isomerization and therefore a different catalyst at more severe operating conditions was employed.

EXAMPLE II The following example offers a comparison of various feedstocks and their effect on the quality of jet fuels produced therefrom. In all runs a palladium on hydrogen form faujasite catalyst was employed. The purity conditions employed and resulting data are set forth in Table II.

TABLE II Run No 1 2 3 4 Feed Wax Heavy Light Heavy Virgin Catalytic Catalytic Gas Oil Cycle Oil Cycle Oil Operating Conditions:

Temperature, F 600 748 656 706 V/v.]l1r 1 l 1 1 Pressure, psi 1,000 1,000 1, 000 1, 000 2 s.o.f./bbl 6, 000 8,000 4, 000 8, 000 Yield of 200/470" F.

Fraction, vol. percent 15.5 60 79 52- Quality of 200/475 F.

Fraction:

Gravity, API 54.1 50.3 41.4 43 .1 Freeze Point, F 88 -76 76 76 Composition, vol.

percent:

Aromatics 10 21 26 40 25 54 60 42 65 25 14 18 Data given in Table II on feedstocks show wax feed to be superior to virgin and catalytic fractions, although these feeds contain some wax components. However, the aromatics and naphthenes concentration in these feeds contribute to the formation of a more aromatic jet fuel, while hydrocracking of wax feed over palladium on hydrogen form faujasite catalyst at low conversion gives low aromatic jet fuel fraction compared to the processing virgin and catalytic gas oils.

EXAMPLE III The following example illustrates the marked difierences in various catalysts utilized in the hydrocracking operation. The wax feed analyzed had inspections similar to that employed in Example I. Resulting data from four typical runs are presented in Table III.

TAB LE III Run No 1 2 3 4 Catalyst 0.5% Palla- Nickel Iron Cobalt dium on Sulfide on Fania- Molyb- Hydrogen Silica site date 1 on Faujasite Alumina 1 Alumina Operating Conditions:

Temperature, F-- 600 750 750 750 V. v./hr 1 1 1 1 I 1, 000 1, 000 1, 000 1, 000 H s.e.f./bbl 6, 000 10, 000 10, 000 10, 000 Yield of C- 470 F., Fraction, vol. percent 38 .6 34.8 1.0 2 .0 Jet Fuel Inspections:

Gravity, APL--- 68 64 Freezing Point, F. -88 88 Luminometer N o 95 90-95 (lgxggglslifitgon, v01. lnsunicient Product Aromatics 2 3 Naphthenes 20 25 Paratfins 78 7 1 Sulfided the catalyst prior to operation.

These data show excellent quality jet fuel may be produced by hydrocracking wax over palladium on hydrogen faujasite and/or nickel sulfide type catalyst. Other forms of faujasite or other zeolite based catalyst and the conventional sulfided cobalt molybdate catalyst referred to in the art, when used at the above treating conditions, are unsatisfactory for the production of jet fuel fractions from wax feed stock.

EXAMPLE IV This example is a comparison of conventional jet fuels produced from hydrocracking wax and from fractions obtained by the distillation of virgin Louisiana crudes.

TABLE IV Feed Source Hydrocracking Wax Distillation of Virgin Catalyst Palladium La. Crudcs on Nickel Sulfide on Hydrogen Silice Alumina Faujasite Fraction C 470 F. C 470" F. ZOO-470 F. C 470 F. 200-470 F. Jet Fuel Inspections:

Gravity, API 68 64 55. 2 58-65 52-53 Freezing PL, F 88 -83 87 88 50 to 60 Luminometer No 95 90-95 66 70-80 40-45 Composition, vol. percent:

Aromatics 2 3 5 7-12 10-15 Naphthenes 2O 25 30 30-35 35-40 Paraifins 78 72 65 50-65 45-50 Jet fuel fractions from hydrocracking wax over the above-identified catalysts at the conditions employed gave improved quality over that obtained by conventional distillation of premium quality Louisiana crudes.

What is claimed is:

1. A process for the production of a fuel of improved burning qualities when burned in a jet combustion device, which comprises contacting a charge stock consisting essentially of parafinic wax having an initial boiling point greater than about 650 F. with a hydrocracking catalyst at a temperature within the range from about 300 to 900 F., a pressure within the range from about 500 to 3000 p.s.i.g., and at an hourly space velocity within the range from about 0.1 to 10 v./v./hr., while in admixture with hydrogen fed in amounts within the range from 2000 to 20,000 s.c.f. H /bbl. of said paraffinic wax.

2. The process of claim 1 in which the hydrocracking catalyst comprises palladium supported on a crystalline alumino-silicate zeolite having a pore size of between 6 to Angstrom units.

3. The process of claim 1 in which the hydrocracking catalyst is nickel sulfide supported on silica/ alumina base.

4. A process for the production of a fuel of improved burning qualities when burned in a jet combustion device, which comprises contacting in a first reaction zone a charge stock consisting essentially of a paraflin-ic wax having an initial boiling point in excess of about 650 F. with a palladium catalyst composited with a crystalline alumino-silicate zeolite, at a temperature within the range from about 400 to 800 F., a pressure within the range from about 500 to 5000 p.s.i.g., and at an hourly space velocity within the range of from about 0.2 to v./v./ hr. while in admixture with hydrogen fed in amounts within the range from 1000 to 20,000 s.c.f. H /bbl. of said wax, whereby a product containing a jet fuel boiling within the range of from about 50 to 480 F. and a higher boiling fraction is produced, separating at least a portion of said higher boiling fraction from said jet fuel, contacting in a second reaction zone said higher boiling fraction with a nickel sulfide catalyst on silica/ alumina base at a temperature within the range from about 400 to 800 F., a pressure within the range from about 500 to 5000 p.s.i.g., and an hourly space velocity within the range from about 0.2 to 20 v./v./ hr. while in admixture with hydrogen fed in amounts within the range of from 1000 to 20,000 s.c.f. H /bb1. and mixing the product resulting from said second reaction zone with the product from said first reaction zone.

5. The process of claim 4 in which the paraffin wax boils within the range of from 1000 to 1300 F.

6. A process for the production of a fuel of improved burning qualities when burned in a jet combustion device which comprises contacting a charge stock consisting essentially of a microcrystalline paraffinic wax having an initial boiling point above about 650 F. with a hydrocracking catalyst at a temperature within the range from about 500 to 750 F., a pressure within the range from about 1000 to 2000 p.s.i.g., and at an hourly space velocity within the range from about 0.5 to 2 v./v./hr. while in admixture with hydrogen fed in amounts within the range from 3000 to 10,000 s.c.f. H /bbl. of said paraffinic wax.

7. The process of claim 6 in which the hydrocracking catalyst comprises palladium supported on a crystalline alumino-silicate zeolite having a pore size of between 6 to 15 Angstrom units.

8. The process of claim 1 in which the paraffin wax has an initial boiling point in the range of from 1000 to 1300 F.

9. A process for the production of a fuel of improved burning qualities when burned in a jet combustion device, which comprises contacting in a first reaction zone a charge stock consisting essentially of a microcrystalline parafiinic wax having an initial boiling point above about 650 F. with a palladium catalyst composited with a crystalline alumino-silicate zeolite, at a temperature within the range from about 550 to 750 F., a pressure within the range from about 1000 to 2000 p.s.i.g., and at an hourly space velocity within the range of from about 0.5 to 2 v./v./hr. while in admixture with hydrogen fed in amounts within the range from 3000 to 10,000 s.c.f. H /bbl. of said wax, whereby a product containing a jet fuel boiling within the range of from about 50 to 480 F. and a higher boiling fraction is produced, separating at least a portion of said higher boiling fraction from said jet fuel, contacting in a second reaction zone said higher boiling fraction with a nickel sulfide catalyst on silica/ alumina base at a temperature within the range from about 550 to 750 F., a pressure within the range from about 1000 to 2000 p.s.i.g., and an hourly space velocity within the range from about 0.5 to 2 v./v./hr. while in admixture with hydrogen fed in amounts within the range of from 3000 to 10,000 s.c.f. H /bbl. and mixing the product resulting from said second reaction zone with the product from said first reaction zone.

References Cited by the Examiner UNITED STATES PATENTS 3,132,087 5/1964 Kelley et a1. 208112 3,153,627 10/1964 Beuther et al. 208- 3,184,404 5/1965 Flinn et al. 208-112 DELBERT E. GANTZ, Primary Examiner.

A. RIMENS, Assistant Examiner. 

1. A PROCESS FOR THE PRODUCTION OF A FUEL OF IMPROVED BURNING QUALITIES WHEN BURNED IN A JET COMBUSTION DEVICE, WHICH COMPRISES CONTACTING A CHARGE STOCK CONSISTING ESSENTIALLY OF PARAFFINIC WAX HAVING AN INITIAL BOILING POINT GREATER THAN ABOUT 650*F. WITH A HYDROCRACKING CATALYST AT A TEMPERATURE WITHIN THE RANGE FROM ABOUT 300 TO 900*F., A PRESSURE WITHIN THE RANGE FROM ABOUT 500 TO 3000 P.S.I.G., AND AT AN HOURLY SPACE VELOCITY WITHIN THE RANGE FROM ABOUT 0.1 TO 10 V./V./HR., WHILE IN ADMIXTURE WITH HYDROGEN FED IN AMOUNTS WITHIN THE RANGE FROM 2000 TO 20,000 S.C.F.H2/BBL. OF SAID PARAFFINIC WAX. 